( -l- )

may per Cei ve by the Diagram, where A B representeth the Object Metal,

C D the Eye Glass, F their common Focus, and O tbe other Focus of theMetal, in which tbe Object is plaeed.

x. A, reprefents a fmall flat Ring ot Braß, whofe Interior Circle muft not sy M/.StiplK-nmuch exceed to of an Inch Diameter, and about j j of an Inch tbick : This Cirav. n. 22S.we may call the Frame or Cell of the daß ; it muß be prepared for use atter ? ’ 54t ‘the following manner. Take a fmall Globule of Quick-Silver, and diflolve r ^. 104..it in a few dtops of Aqua Fortis, to which you may add 10 parts ot com-mon Water i dip the end of a Stick in this Liquor, and ruo the in ward Cir-cle of the Ring with it; fb it will lia ve acquired a Mercurial Tincture, andbcing wiped dry, be fit for use. Then let it be laid on the Table, and poura drop ot Qjiick-silver within it, which preß gcntly with the Ball of the Fin-ger, and it will adhere to the Ring ; then cleanfe it with a Hare’s Foot, andyou will have a Convex Speculum. Take up the Ring and Speculum carry-ing it Horizontal, and lay it on the Brims of the hollow Cylinder B ; (o willthe Mercury become a Concave Reflecting Speculum, which from the fmali-nefs of the Sphere of which it feems.to bc a Section, may be ufed as a Mi-croscopc. The Cylindrick Veflel B, has a Skrew Hole at the bottom, bywhich it is skrewed to the top of the Pedestal CD; C EF G is the Suppor-ter of the Object Piate, which as you fce.may be raifed higher, or let lower,as there is occasion, by the Skrew on the Pedestal : The Object Piate mußbe of Glass cemented to the Ring G.

This Instrument with a little Variation may be made a Microfcopc ofWater, if instead of the Ring G, there be only a frmll Arm with a Hole init to rcceive a Drop of Water, and the Cylindrick Veflel B, be either takenaway or skrewed on with its bottom upwards, fb as to make an Object Piate.

This will be more convenient for viewing the Textures of Öpacous Objects,than that abave deferibed, which is more fit for Fluid and Transparent ones.

XXVII. 1. The Figure of it is Round, being 30 Inches, and fbmewhat ^ niirn ;,^ Co „Better, in Diameter. On one side it hath a Frame of a Circle of Steel, to Ljons,the end that it may keep its just Meafüre : ’Tis casie to remove it from place macleto place, though it be above an hundred weighr, and ’tis easily put in all forts J u ' ö '~öf Postures. The Burning Point is distant from the Center of tbe Glass a-bout 3 Foot. The Focus is about half a Ltuis / Or large. One may parisone’s Hand through it, if it be done nimbly ; for if icftuy there the time ofa Second Minute, there is danger of reeeiving much hurt. Green Woodtakes Fire in it in an instant, as do also many other Bodies.

Seeonds.

A fmall Piece of Pot-Iron was meited, and rcady tadrop down in—40

A Sil ver Piece of .Fifteen .Penee was piereed in .. ■■■■■ —14

A Gross Nail (callcd U Claude Paijan) was meited in 1 ♦— 30

The end of a Sword, Blade of Oliude, was bum’d in — - --—43

A Brass Counter was piereed in - > . . . «■ ... ■ .. . - . a

A piece of Red Copper was meited ready to drop-dövra, in— “4X

E e x ''' ’• Ä